Field
Apparatuses and methods consistent with exemplary embodiments relate to cancelling an acoustic echo, and more particularly to minimizing an effect on a filter adapting process for cancelling an acoustic echo by precisely sensing a double-talk state.
Description of the Related Art
In an electronic device such as a communication terminal, a voice of a far-end speaker may be echoed by a surrounding environment and then input through a nearby speaker. The sound of the voice reverberating in the electronic device may be referred to as an acoustic echo.
A recent display apparatus such as a smart television (TV) frequently includes a microphone to perform a voice recognition function. Therefore, there are demands for a method of cancelling an acoustic echo that may be used in various types of electronic devices including a communication terminal.
A related-art acoustic echo canceller as shown in FIG. 1 is used to cancel an acoustic echo as described above. A far-end speaker signal x(n) output through a speaker becomes an echo signal h(n)*x(n) through a surrounding environment and then input into a near-end microphone. An adaptive filter cancels ĥ(n)*x(n) from a signal d(n) input into the microphone by estimating an estimation value ĥ(n) of h(n) corresponding to an acoustic echo path. Therefore, the related-art acoustic echo canceller reduces an effect by the far-end speaker signal.
A problem of this method is a double-talk state where an echo signal h(n)*x(n) of the far-end speaker signal and a signal s(n) of a near-end speaker are simultaneously input. If the estimation value ĥ(n) is determined to cancel a near-end signal together from the adaptive filter, a real acoustic echo path is not reflected.
In order to address this double-talk problem in the related technology, a method of finding an algorithm robust to a double-talk state is examined. However, if the method is applied to a real product, a satisfactory effect is not acquired.
Also, in the related technology, if the double-talk state is sensed by using a cross-correlation between the output signal x(n) of the far-end speaker and the input signal d(n) of the near-end speaker, a method of stopping an operation of the adaptive filter is provided. However, there is a problem where many computing resources for a cross-correlation computation are consumed. Also, there is a problem where completely stopping the operation of the adaptive filter is not efficient.